diff --git a/sphinx/builders/__init__.py b/sphinx/builders/__init__.py
index 2a28fd1c4..996a8c6a5 100644
--- a/sphinx/builders/__init__.py
+++ b/sphinx/builders/__init__.py
@@ -19,7 +19,6 @@ except ImportError:
     multiprocessing = threading = None
 
 from docutils import nodes
-from six import string_types
 
 from sphinx.util import i18n, path_stabilize
 from sphinx.util.osutil import SEP, relative_uri, find_catalog
diff --git a/sphinx/builders/devhelp.py b/sphinx/builders/devhelp.py
index 8e334b3f6..e6199e621 100644
--- a/sphinx/builders/devhelp.py
+++ b/sphinx/builders/devhelp.py
@@ -33,6 +33,7 @@ except ImportError:
 
 try:
     import gzip
+
     def comp_open(filename, mode='rb'):
         return gzip.open(filename + '.gz', mode)
 except ImportError:
@@ -81,7 +82,7 @@ class DevhelpBuilder(StandaloneHTMLBuilder):
 
         def write_toc(node, parent):
             if isinstance(node, addnodes.compact_paragraph) or \
-                   isinstance(node, nodes.bullet_list):
+               isinstance(node, nodes.bullet_list):
                 for subnode in node:
                     write_toc(subnode, parent)
             elif isinstance(node, nodes.list_item):
@@ -94,7 +95,7 @@ class DevhelpBuilder(StandaloneHTMLBuilder):
 
         def istoctree(node):
             return isinstance(node, addnodes.compact_paragraph) and \
-                   'toctree' in node
+                'toctree' in node
 
         for node in tocdoc.traverse(istoctree):
             write_toc(node, chapters)
diff --git a/sphinx/builders/epub.py b/sphinx/builders/epub.py
index 9b0c34c49..cdcfed2b7 100644
--- a/sphinx/builders/epub.py
+++ b/sphinx/builders/epub.py
@@ -40,7 +40,7 @@ from sphinx.util.console import brown
 # output but that may be customized by (re-)setting module attributes,
 # e.g. from conf.py.
 
-_mimetype_template = 'application/epub+zip' # no EOL!
+_mimetype_template = 'application/epub+zip'  # no EOL!
 
 _container_template = u'''\
 <?xml version="1.0" encoding="UTF-8"?>
@@ -221,10 +221,10 @@ class EpubBuilder(StandaloneHTMLBuilder):
         if isinstance(doctree, nodes.reference) and 'refuri' in doctree:
             refuri = doctree['refuri']
             if refuri.startswith('http://') or refuri.startswith('https://') \
-                or refuri.startswith('irc:') or refuri.startswith('mailto:'):
+               or refuri.startswith('irc:') or refuri.startswith('mailto:'):
                 return result
             classes = doctree.parent.attributes['classes']
-            for level in range(8, 0, -1): # or range(1, 8)?
+            for level in range(8, 0, -1):  # or range(1, 8)?
                 if (_toctree_template % level) in classes:
                     result.append({
                         'level': level,
@@ -242,11 +242,12 @@ class EpubBuilder(StandaloneHTMLBuilder):
         and pre and post files not managed by sphinx.
         """
         doctree = self.env.get_and_resolve_doctree(self.config.master_doc,
-            self, prune_toctrees=False, includehidden=True)
+                                                   self, prune_toctrees=False,
+                                                   includehidden=True)
         self.refnodes = self.get_refnodes(doctree, [])
         master_dir = path.dirname(self.config.master_doc)
         if master_dir:
-            master_dir += '/' # XXX or os.sep?
+            master_dir += '/'  # XXX or os.sep?
             for item in self.refnodes:
                 item['refuri'] = master_dir + item['refuri']
         self.toc_add_files(self.refnodes)
@@ -258,7 +259,7 @@ class EpubBuilder(StandaloneHTMLBuilder):
             'level': 1,
             'refuri': self.esc(self.config.master_doc + '.html'),
             'text': ssp(self.esc(
-                    self.env.titles[self.config.master_doc].astext()))
+                self.env.titles[self.config.master_doc].astext()))
         })
         for file, text in reversed(self.config.epub_pre_files):
             refnodes.insert(0, {
@@ -392,7 +393,7 @@ class EpubBuilder(StandaloneHTMLBuilder):
                         m = _refuri_re.match(link)
                         if m:
                             subentrylinks[i] = (ismain,
-                                self.fix_fragment(m.group(1), m.group(2)))
+                                                self.fix_fragment(m.group(1), m.group(2)))
 
     def is_vector_graphics(self, filename):
         """Does the filename extension indicate a vector graphic format?"""
@@ -461,8 +462,7 @@ class EpubBuilder(StandaloneHTMLBuilder):
         if pagename.startswith('genindex'):
             self.fix_genindex(addctx['genindexentries'])
         StandaloneHTMLBuilder.handle_page(self, pagename, addctx, templatename,
-            outfilename, event_arg)
-
+                                          outfilename, event_arg)
 
     # Finish by building the epub file
     def handle_finish(self):
@@ -529,9 +529,9 @@ class EpubBuilder(StandaloneHTMLBuilder):
         olen = len(outdir)
         projectfiles = []
         self.files = []
-        self.ignored_files = ['.buildinfo',
-            'mimetype', 'content.opf', 'toc.ncx', 'META-INF/container.xml',
-            self.config.epub_basename + '.epub'] + \
+        self.ignored_files = ['.buildinfo', 'mimetype', 'content.opf',
+                              'toc.ncx', 'META-INF/container.xml',
+                              self.config.epub_basename + '.epub'] + \
             self.config.epub_exclude_files
         for root, dirs, files in os.walk(outdir):
             for fn in files:
@@ -579,7 +579,7 @@ class EpubBuilder(StandaloneHTMLBuilder):
             image, html_tmpl = self.config.epub_cover
             image = image.replace(os.sep, '/')
             mpos = content_tmpl.rfind('</metadata>')
-            cpos = content_tmpl.rfind('\n', 0 , mpos) + 1
+            cpos = content_tmpl.rfind('\n', 0, mpos) + 1
             content_tmpl = content_tmpl[:cpos] + \
                 _cover_template % {'cover': self.esc(self.make_id(image))} + \
                 content_tmpl[cpos:]
@@ -596,7 +596,7 @@ class EpubBuilder(StandaloneHTMLBuilder):
                     })
                 ctx = {'image': self.esc(image), 'title': self.config.project}
                 self.handle_page(
-                        path.splitext(_coverpage_name)[0], ctx, html_tmpl)
+                    path.splitext(_coverpage_name)[0], ctx, html_tmpl)
 
         guide = []
         auto_add_cover = True
@@ -611,22 +611,22 @@ class EpubBuilder(StandaloneHTMLBuilder):
                 if type == 'toc':
                     auto_add_toc = False
                 guide.append(_guide_template % {
-                        'type': self.esc(type),
-                        'title': self.esc(title),
-                        'uri': self.esc(uri)
-                        })
+                    'type': self.esc(type),
+                    'title': self.esc(title),
+                    'uri': self.esc(uri)
+                })
         if auto_add_cover and html_tmpl:
             guide.append(_guide_template % {
-                    'type': 'cover',
-                    'title': _guide_titles['cover'],
-                    'uri': self.esc(_coverpage_name)
-                    })
+                'type': 'cover',
+                'title': _guide_titles['cover'],
+                'uri': self.esc(_coverpage_name)
+            })
         if auto_add_toc and self.refnodes:
             guide.append(_guide_template % {
-                    'type': 'toc',
-                    'title': _guide_titles['toc'],
-                    'uri': self.esc(self.refnodes[0]['refuri'])
-                    })
+                'type': 'toc',
+                'title': _guide_titles['toc'],
+                'uri': self.esc(self.refnodes[0]['refuri'])
+            })
         projectfiles = '\n'.join(projectfiles)
         spine = '\n'.join(spine)
         guide = '\n'.join(guide)
@@ -635,7 +635,7 @@ class EpubBuilder(StandaloneHTMLBuilder):
         f = codecs.open(path.join(outdir, outname), 'w', 'utf-8')
         try:
             f.write(content_tmpl %
-                self.content_metadata(projectfiles, spine, guide))
+                    self.content_metadata(projectfiles, spine, guide))
         finally:
             f.close()
 
@@ -719,7 +719,8 @@ class EpubBuilder(StandaloneHTMLBuilder):
 
         if self.config.epub_tocscope == 'default':
             doctree = self.env.get_and_resolve_doctree(self.config.master_doc,
-                self, prune_toctrees=False, includehidden=False)
+                                                       self, prune_toctrees=False,
+                                                       includehidden=False)
             refnodes = self.get_refnodes(doctree, [])
             self.toc_add_files(refnodes)
         else:
@@ -744,9 +745,9 @@ class EpubBuilder(StandaloneHTMLBuilder):
         projectfiles = ['META-INF/container.xml', 'content.opf', 'toc.ncx'] \
             + self.files
         epub = zipfile.ZipFile(path.join(outdir, outname), 'w',
-            zipfile.ZIP_DEFLATED)
+                               zipfile.ZIP_DEFLATED)
         epub.write(path.join(outdir, 'mimetype'), 'mimetype',
-            zipfile.ZIP_STORED)
+                   zipfile.ZIP_STORED)
         for file in projectfiles:
             fp = path.join(outdir, file)
             epub.write(fp, file, zipfile.ZIP_DEFLATED)
diff --git a/sphinx/builders/gettext.py b/sphinx/builders/gettext.py
index 63beb4941..c23675d36 100644
--- a/sphinx/builders/gettext.py
+++ b/sphinx/builders/gettext.py
@@ -130,6 +130,7 @@ timestamp = time()
 tzdelta = datetime.fromtimestamp(timestamp) - \
     datetime.utcfromtimestamp(timestamp)
 
+
 class LocalTimeZone(tzinfo):
 
     def __init__(self, *args, **kw):
@@ -213,8 +214,8 @@ class MessageCatalogBuilder(I18nBuilder):
 
                     if self.config.gettext_location:
                         # generate "#: file1:line1\n#: file2:line2 ..."
-                        pofile.write("#: %s\n" % "\n#: ".join("%s:%s" %
-                            (safe_relpath(source, self.outdir), line)
+                        pofile.write("#: %s\n" % "\n#: ".join(
+                            "%s:%s" % (safe_relpath(source, self.outdir), line)
                             for source, line, _ in positions))
                     if self.config.gettext_uuid:
                         # generate "# uuid1\n# uuid2\n ..."
@@ -223,8 +224,8 @@ class MessageCatalogBuilder(I18nBuilder):
 
                     # message contains *one* line of text ready for translation
                     message = message.replace('\\', r'\\'). \
-                                      replace('"', r'\"'). \
-                                      replace('\n', '\\n"\n"')
+                        replace('"', r'\"'). \
+                        replace('\n', '\\n"\n"')
                     pofile.write('msgid "%s"\nmsgstr ""\n\n' % message)
 
             finally:
diff --git a/sphinx/builders/html.py b/sphinx/builders/html.py
index e60eb3a0a..3a617bb67 100644
--- a/sphinx/builders/html.py
+++ b/sphinx/builders/html.py
@@ -78,7 +78,7 @@ class StandaloneHTMLBuilder(Builder):
     searchindex_filename = 'searchindex.js'
     add_permalinks = True
     embedded = False  # for things like HTML help or Qt help: suppresses sidebar
-    search = True # for things like HTML help and Apple help: suppress search
+    search = True  # for things like HTML help and Apple help: suppress search
 
     # This is a class attribute because it is mutated by Sphinx.add_javascript.
     script_files = ['_static/jquery.js', '_static/underscore.js',
@@ -194,7 +194,7 @@ class StandaloneHTMLBuilder(Builder):
         except Exception:
             pass
         if old_config_hash != self.config_hash or \
-               old_tags_hash != self.tags_hash:
+           old_tags_hash != self.tags_hash:
             for docname in self.env.found_docs:
                 yield docname
             return
@@ -230,8 +230,8 @@ class StandaloneHTMLBuilder(Builder):
 
         if self._publisher is None:
             self._publisher = Publisher(
-                    source_class = DocTreeInput,
-                    destination_class=StringOutput)
+                source_class = DocTreeInput,
+                destination_class=StringOutput)
             self._publisher.set_components('standalone',
                                            'restructuredtext', 'pseudoxml')
 
@@ -280,7 +280,7 @@ class StandaloneHTMLBuilder(Builder):
                             continue
                     # deprecated config value
                     if indexname == 'py-modindex' and \
-                           not self.config.html_use_modindex:
+                       not self.config.html_use_modindex:
                         continue
                     content, collapse = indexcls(domain).generate()
                     if content:
@@ -296,10 +296,10 @@ class StandaloneHTMLBuilder(Builder):
             self.last_updated = None
 
         logo = self.config.html_logo and \
-               path.basename(self.config.html_logo) or ''
+            path.basename(self.config.html_logo) or ''
 
         favicon = self.config.html_favicon and \
-                  path.basename(self.config.html_favicon) or ''
+            path.basename(self.config.html_favicon) or ''
         if favicon and os.path.splitext(favicon)[1] != '.ico':
             self.warn('html_favicon is not an .ico file')
 
@@ -394,8 +394,9 @@ class StandaloneHTMLBuilder(Builder):
                 pass
             related = self.relations.get(related[0])
         if parents:
-            parents.pop() # remove link to the master file; we have a generic
-                          # "back to index" link already
+            # remove link to the master file; we have a generic
+            # "back to index" link already
+            parents.pop()
         parents.reverse()
 
         # title rendered as HTML
@@ -505,7 +506,7 @@ class StandaloneHTMLBuilder(Builder):
         # the entries into two columns
         genindex = self.env.create_index(self)
         indexcounts = []
-        for _, entries in genindex:
+        for _k, entries in genindex:
             indexcounts.append(sum(1 + len(subitems)
                                    for _, (_, subitems) in entries))
 
@@ -821,8 +822,7 @@ class StandaloneHTMLBuilder(Builder):
                      u'# Project: %s\n'
                      u'# Version: %s\n'
                      u'# The remainder of this file is compressed using zlib.\n'
-                     % (self.config.project, self.config.version)
-                    ).encode('utf-8'))
+                     % (self.config.project, self.config.version)).encode('utf-8'))
             compressor = zlib.compressobj(9)
             for domainname, domain in iteritems(self.env.domains):
                 for name, dispname, type, docname, anchor, prio in \
@@ -835,8 +835,7 @@ class StandaloneHTMLBuilder(Builder):
                         dispname = u'-'
                     f.write(compressor.compress(
                         (u'%s %s:%s %s %s %s\n' % (name, domainname, type,
-                                                   prio, uri, dispname)
-                        ).encode('utf-8')))
+                                                   prio, uri, dispname)).encode('utf-8')))
             f.write(compressor.flush())
         finally:
             f.close()
@@ -874,13 +873,13 @@ class DirectoryHTMLBuilder(StandaloneHTMLBuilder):
         if docname == 'index':
             return ''
         if docname.endswith(SEP + 'index'):
-            return docname[:-5] # up to sep
+            return docname[:-5]  # up to sep
         return docname + SEP
 
     def get_outfilename(self, pagename):
         if pagename == 'index' or pagename.endswith(SEP + 'index'):
-            outfilename = path.join(self.outdir, os_path(pagename)
-                                    + self.out_suffix)
+            outfilename = path.join(self.outdir, os_path(pagename) +
+                                    self.out_suffix)
         else:
             outfilename = path.join(self.outdir, os_path(pagename),
                                     'index' + self.out_suffix)
@@ -907,7 +906,7 @@ class SingleFileHTMLBuilder(StandaloneHTMLBuilder):
         if docname in self.env.all_docs:
             # all references are on the same page...
             return self.config.master_doc + self.out_suffix + \
-                   '#document-' + docname
+                '#document-' + docname
         else:
             # chances are this is a html_additional_page
             return docname + self.out_suffix
@@ -1053,7 +1052,7 @@ class SerializingHTMLBuilder(StandaloneHTMLBuilder):
         if docname == 'index':
             return ''
         if docname.endswith(SEP + 'index'):
-            return docname[:-5] # up to sep
+            return docname[:-5]  # up to sep
         return docname + SEP
 
     def dump_context(self, context, filename):
diff --git a/sphinx/builders/htmlhelp.py b/sphinx/builders/htmlhelp.py
index 8085ee145..9a21fb15b 100644
--- a/sphinx/builders/htmlhelp.py
+++ b/sphinx/builders/htmlhelp.py
@@ -191,7 +191,7 @@ class HTMLHelpBuilder(StandaloneHTMLBuilder):
     def open_file(self, outdir, basename, mode='w'):
         # open a file with the correct encoding for the selected language
         return codecs.open(path.join(outdir, basename), mode,
-            self.encoding, 'xmlcharrefreplace')
+                           self.encoding, 'xmlcharrefreplace')
 
     def handle_finish(self):
         self.build_hhx(self.outdir, self.config.htmlhelp_basename)
@@ -220,7 +220,7 @@ class HTMLHelpBuilder(StandaloneHTMLBuilder):
                 staticdir = root.startswith(path.join(outdir, '_static'))
                 for fn in files:
                     if (staticdir and not fn.endswith('.js')) or \
-                           fn.endswith('.html'):
+                       fn.endswith('.html'):
                         print(path.join(root, fn)[olen:].replace(os.sep, '\\'),
                               file=f)
         finally:
@@ -239,6 +239,7 @@ class HTMLHelpBuilder(StandaloneHTMLBuilder):
             # the TOC
             tocdoc = self.env.get_and_resolve_doctree(
                 self.config.master_doc, self, prune_toctrees=False)
+
             def write_toc(node, ullevel=0):
                 if isinstance(node, nodes.list_item):
                     f.write('<LI> ')
@@ -246,7 +247,7 @@ class HTMLHelpBuilder(StandaloneHTMLBuilder):
                         write_toc(subnode, ullevel)
                 elif isinstance(node, nodes.reference):
                     link = node['refuri']
-                    title = htmlescape(node.astext()).replace('"','&quot;')
+                    title = htmlescape(node.astext()).replace('"', '&quot;')
                     f.write(object_sitemap % (title, link))
                 elif isinstance(node, nodes.bullet_list):
                     if ullevel != 0:
@@ -258,9 +259,10 @@ class HTMLHelpBuilder(StandaloneHTMLBuilder):
                 elif isinstance(node, addnodes.compact_paragraph):
                     for subnode in node:
                         write_toc(subnode, ullevel)
+
             def istoctree(node):
                 return isinstance(node, addnodes.compact_paragraph) and \
-                       'toctree' in node
+                    'toctree' in node
             for node in tocdoc.traverse(istoctree):
                 write_toc(node)
             f.write(contents_footer)
@@ -272,6 +274,7 @@ class HTMLHelpBuilder(StandaloneHTMLBuilder):
         f = self.open_file(outdir, outname+'.hhk')
         try:
             f.write('<UL>\n')
+
             def write_index(title, refs, subitems):
                 def write_param(name, value):
                     item = '    <param name="%s" value="%s">\n' % \
diff --git a/sphinx/builders/latex.py b/sphinx/builders/latex.py
index ee3f0bb7e..f0c1d3a7c 100644
--- a/sphinx/builders/latex.py
+++ b/sphinx/builders/latex.py
@@ -45,7 +45,7 @@ class LaTeXBuilder(Builder):
         texescape.init()
 
     def get_outdated_docs(self):
-        return 'all documents' # for now
+        return 'all documents'  # for now
 
     def get_target_uri(self, docname, typ=None):
         if docname not in self.docnames:
@@ -94,9 +94,9 @@ class LaTeXBuilder(Builder):
                 destination_path=path.join(self.outdir, targetname),
                 encoding='utf-8')
             self.info("processing " + targetname + "... ", nonl=1)
-            doctree = self.assemble_doctree(docname, toctree_only,
-                appendices=((docclass != 'howto') and
-                            self.config.latex_appendices or []))
+            doctree = self.assemble_doctree(
+                docname, toctree_only,
+                appendices=((docclass != 'howto') and self.config.latex_appendices or []))
             self.post_process_images(doctree)
             self.info("writing... ", nonl=1)
             doctree.settings = docsettings
diff --git a/sphinx/builders/manpage.py b/sphinx/builders/manpage.py
index 0745f6e60..0176621f5 100644
--- a/sphinx/builders/manpage.py
+++ b/sphinx/builders/manpage.py
@@ -37,7 +37,7 @@ class ManualPageBuilder(Builder):
                       'will be written')
 
     def get_outdated_docs(self):
-        return 'all manpages' # for now
+        return 'all manpages'  # for now
 
     def get_target_uri(self, docname, typ=None):
         if typ == 'token':
diff --git a/sphinx/builders/qthelp.py b/sphinx/builders/qthelp.py
index 4d13dd4fa..825f5651f 100644
--- a/sphinx/builders/qthelp.py
+++ b/sphinx/builders/qthelp.py
@@ -111,7 +111,7 @@ class QtHelpBuilder(StandaloneHTMLBuilder):
         StandaloneHTMLBuilder.init(self)
         # the output files for HTML help must be .html only
         self.out_suffix = '.html'
-        #self.config.html_style = 'traditional.css'
+        # self.config.html_style = 'traditional.css'
 
     def handle_finish(self):
         self.build_qhp(self.outdir, self.config.qthelp_basename)
@@ -122,9 +122,10 @@ class QtHelpBuilder(StandaloneHTMLBuilder):
         # sections
         tocdoc = self.env.get_and_resolve_doctree(self.config.master_doc, self,
                                                   prune_toctrees=False)
-        istoctree = lambda node: (
-                        isinstance(node, addnodes.compact_paragraph)
-                            and 'toctree' in node)
+
+        def istoctree(node):
+            return isinstance(node, addnodes.compact_paragraph) and \
+                'toctree' in node
         sections = []
         for node in tocdoc.traverse(istoctree):
             sections.extend(self.write_toc(node))
@@ -160,10 +161,10 @@ class QtHelpBuilder(StandaloneHTMLBuilder):
         imagesdir = path.join(outdir, self.imagedir)
         for root, dirs, files in os.walk(outdir):
             resourcedir = root.startswith(staticdir) or \
-                          root.startswith(imagesdir)
+                root.startswith(imagesdir)
             for fn in files:
                 if (resourcedir and not fn.endswith('.js')) or \
-                       fn.endswith('.html'):
+                   fn.endswith('.html'):
                     filename = path.join(root, fn)[olen:]
                     projectfiles.append(file_template %
                                         {'filename': htmlescape(filename)})
@@ -239,7 +240,7 @@ class QtHelpBuilder(StandaloneHTMLBuilder):
                 parts.extend(self.write_toc(subnode, indentlevel))
         elif isinstance(node, nodes.reference):
             link = node['refuri']
-            title = htmlescape(node.astext()).replace('"','&quot;')
+            title = htmlescape(node.astext()).replace('"', '&quot;')
             item = section_template % {'title': title, 'ref': link}
             item = u' ' * 4 * indentlevel + item
             parts.append(item.encode('ascii', 'xmlcharrefreplace'))
@@ -258,7 +259,7 @@ class QtHelpBuilder(StandaloneHTMLBuilder):
             groupdict = matchobj.groupdict()
             shortname = groupdict['title']
             id = groupdict.get('id')
-            #descr = groupdict.get('descr')
+            # descr = groupdict.get('descr')
             if shortname.endswith('()'):
                 shortname = shortname[:-2]
             id = '%s.%s' % (id, shortname)
@@ -277,17 +278,17 @@ class QtHelpBuilder(StandaloneHTMLBuilder):
         keywords = []
 
         title = htmlescape(title)
-#        if len(refs) == 0: # XXX
-#            write_param('See Also', title)
+        # if len(refs) == 0: # XXX
+        #     write_param('See Also', title)
         if len(refs) == 1:
             keywords.append(self.keyword_item(title, refs[0]))
         elif len(refs) > 1:
             for i, ref in enumerate(refs):  # XXX
-#                item = (' '*12 +
-#                        '<keyword name="%s [%d]" ref="%s"/>' % (
-#                                                        title, i, ref))
-#                item.encode('ascii', 'xmlcharrefreplace')
-#                keywords.append(item)
+                # item = (' '*12 +
+                #         '<keyword name="%s [%d]" ref="%s"/>' % (
+                #          title, i, ref))
+                # item.encode('ascii', 'xmlcharrefreplace')
+                # keywords.append(item)
                 keywords.append(self.keyword_item(title, ref))
 
         if subitems:
diff --git a/sphinx/builders/texinfo.py b/sphinx/builders/texinfo.py
index cdabeb3a8..3adeec404 100644
--- a/sphinx/builders/texinfo.py
+++ b/sphinx/builders/texinfo.py
@@ -88,14 +88,14 @@ class TexinfoBuilder(Builder):
     name = 'texinfo'
     format = 'texinfo'
     supported_image_types = ['image/png', 'image/jpeg',
-                             'image/gif',]
+                             'image/gif']
 
     def init(self):
         self.docnames = []
         self.document_data = []
 
     def get_outdated_docs(self):
-        return 'all documents' # for now
+        return 'all documents'  # for now
 
     def get_target_uri(self, docname, typ=None):
         if docname not in self.docnames:
@@ -141,7 +141,8 @@ class TexinfoBuilder(Builder):
                 destination_path=path.join(self.outdir, targetname),
                 encoding='utf-8')
             self.info("processing " + targetname + "... ", nonl=1)
-            doctree = self.assemble_doctree(docname, toctree_only,
+            doctree = self.assemble_doctree(
+                docname, toctree_only,
                 appendices=(self.config.texinfo_appendices or []))
             self.info("writing... ", nonl=1)
             self.post_process_images(doctree)
diff --git a/sphinx/builders/xml.py b/sphinx/builders/xml.py
index 44ced5419..18d8cbfb5 100644
--- a/sphinx/builders/xml.py
+++ b/sphinx/builders/xml.py
@@ -19,6 +19,7 @@ from sphinx.builders import Builder
 from sphinx.util.osutil import ensuredir, os_path
 from sphinx.writers.xml import XMLWriter, PseudoXMLWriter
 
+
 class XMLBuilder(Builder):
     """
     Builds Docutils-native XML.